Whorwell PJ; Prior A; Faragher EB. Controlled trial of hypnotherapy in the treatment of severe refractory irritable-bowel syndrome.The Lancet 1984, 2: 1232-4. This was the earliest formal study of hypnosis treatment for IBS and remains to date one of the best studies in this research area, as it was thoroughly placebo-controlled and showed dramatically greater improvement from hypnosis treatment above the placebo. Thirty patients with severe symptoms that had been unresponsive to other treatment were randomly chosen to receive either 7 sessions of hypnotherapy (15 patients) or 7 sessions of psychotherapy plus placebo pills (15 patients). The psychotherapy group showed a small but significant improvement in abdominal pain and distension, and in general well-being but not bowel activity pattern. The hypnotherapy patients showed a dramatic improvement in all IBS symptoms. The hypnotherapy group showed no relapses during the 3-month follow-up period.

Figure adapted from the above paper by Whorwell and colleagues, showing the changes in the hypnosis group and the comparison treatment group in well-being (upper left-hand graph) and IBS symptoms during the 2-week baseline and 12-week treatment period:


Whorwell PJ; Prior A; Colgan SM. Hypnotherapy in severe irritable bowel syndrome: further experience. Gut, 1987 Apr, 28:4, 423-5. This report summed up further experience after 35 patients were added to the initial 15 treated with hypnotherapy in their earlier 1984 Lancet study. For the whole combined 50 patient group, success rate was 95% for classic IBS cases, but substantially less for IBS patients with atypical symptom picture or significant psychological problems. The report also observed that patients over age 50 seemed to have lower success rate from this treatment.

Harvey RF; Hinton RA; Gunary RM; Barry RE. Individual and group hypnotherapy in treatment of refractory irritable bowel syndrome. Lancet, 1989 Feb, 1:8635, 424-5. This study employed a shorter hypnosis treatment course for IBS than used in most other studies. Twenty out of 33 patients with refractory irritable bowel syndrome treated with four sessions of hypnotherapy in this study improved. Improvement was maintained at a 3-month treatment. The researchers further found that hypnosis treatment for IBS in groups of up to 8 patients seemed to be as effective as individual therapy.

Prior A, Colgan SM, Whorwell PJ. Changes in rectal sensitivity after hypnotherapy in patients with irritable bowel syndrome. Gut 1990;31:896. This study found IBS patients to be less sensitive to pain and other sensations induced via balloon inflation in their gut while they were under hypnosis. Sensitivity to some balloon-induced gut sensations (although not pain sensitivity) was reduced following a course of hypnosis treatment as well.

Houghton LA; Heyman DJ; Whorwell PJ. Symptomatology, quality of life and economic features of irritable bowel syndrome--the effect of hypnotherapy. Aliment Pharmacol Ther, 1996 Feb, 10:1, 91-5. This study compared 25 severe IBS patients treated with hypnosis to 25 patients with similar symptom severity treated with other methods, and demonstrated that in addition to significant improvement in all central IBS symptoms, hypnotherapy recipients had fewer visits to doctors, lost less time from work than the control group, and rated their quality of life more improved. Those patients who had been unable to work prior to treatment resumed employment in the hypnotherapy group but not in the control group. The study is notable in that it quantified the substantial economic benefits and improvement in health-related quality of life which results from hypnotherapy for IBS on top of clinical symptom improvement.

Koutsomanis D. Hypnoanalgesia in the irritable bowel syndrome. Gastroenterology 1997, 112, A764. This French study showed less analgesic medication use required and less abdominal pain experienced by a group of 12 IBS patients after a course of 6-8 analgesia-oriented hypnosis sessions followed by 4 sessions of autogenic training. Patients were evaluated at 6-month and 12-month follow-up.

Vidakovic Vukic M. Hypnotherapy in the treatment of irritable bowel syndrome: methods and results in Amsterdam. Scand J Gastroenterol Suppl, 1999, 230:49-51. This paper reports the results of treatment of 27 Dutch patients treated with gut-directed hypnotherapy tailored to each individual patient. All of the 24 patients who completed treatment were found to be improve.

Galovski TE; Blanchard EB. Appl Psychophysiol Biofeedback, 1998 Dec, 23:4, 219-32. Eleven patients completed hypnotherapy, with improvement reported for all central IBS symptoms, as well as improvement in anxiety. Six of the patients were a waiting-control group for comparison, and did not show such improvement while waiting for treatment.

Forbes A, MacAuley S, Chiotakakou-Faliakou E. Hypnotherapy and therapeutic audiotape: effective in previously unsuccessfully treated irritable bowel syndrome? Int J Colorectal Dis. 2000 Nov;15(5-6):328-34. This study compared the impact on symptoms of non-hypnosis therapeutic audiotape (27 patients) versus gut-directed individual hypnotherapy with a therapist (25 patients). Among the 45 treated patients in the study that completed all evaluations in the study, only the hypnotherapy group showed significant reduction in IBS symptom scores.

Gonsalkorale WM, Houghton LA, Whorwell PJ. Hypnotherapy in irritable bowel syndrome: a large-scale audit of a clinical service with examination of factors influencing responsiveness. Am J Gastroenterol 2002 Apr;97(4):954-61. This paper reported outcomes for 250 consecutive IBS patients treated in a hypnos clinic in Manchester, England, using a structured course of 12 sessions of hypnotherapy over a 3-month period plus home practice with audio recordings between sessions. Marked improvement was seen in all IBS symptoms (overall IBS severity was reduced by more than half on the average after treatment), quality of life, and anxiety and depression. All subgroups of patients appeared to do equally well except males with diarrhea, who improved far less than other patients for unknown reason.

Palsson OS, Turner MJ, Johnson DA, Burnett CK, Whitehead WE. Hypnosis treatment for severe irritable bowel syndrome: investigation of mechanism and effects on symptoms. Dig Dis Sci 2002 Nov;47(11):2605-14. This paper describes two studies assessing the impact of hypnosis treatment using the standardized North Carolina protocol on IBS symptoms and possible physiological and psychological mechanisms underlying the the treatment effects. Patients with severe IBS received seven biweekly hypnosis sessions and used hypnosis audio recordings at home in between therapy visits. Bowel pain thresholds and smooth muscle tone were measured with computer-controlled balloon inflation tests before and after treatment in 18 patients (study I), and treatment changes in heart rate, blood pressure, sweat gland activity, finger temperature, and forehead muscle activity were assessed in 24 patients (study II). Somatization, anxiety, and depression were also measured. All central IBS symptoms improved substantially from treatment in both studies. Rectal pain thresholds, rectal smooth muscle tone and autonomic functioning (except sweat gland reactivity) were unaffected by hypnosis treatment. However, the number and severity of non-gastrointestinal symptoms and psychological distress showed large decreases. Improvements in bowel symptoms were unrelated to changes in the physiological parameters measured. 17 of 18 patients in study 1 (94%) and 21 of 24 patients in study 2 (87.5%) were judged to be treatment responders. Improvement was well-maintained at 10-12 month follow up in study 2.

Lea R, Houghton LA, Calvert EL, Larder S, Gonsalkorale WM, Whelan V, Randles J, Cooper P, Cruickshanks P, Miller V, Whorwell PJ. Gut-focused hypnotherapy normalizes disordered rectal sensitivity in patients with irritable bowel syndrome.Alimentary Pharmacology& Therapeutics 2003 Mar 1;17(5):635-42. This study evaluated changes in rectal sensitivity to stimuli in IBS patients who received hypnotherapy. Twenty-three IBS patients were tested with balloon inflation test in their rectum before and after 12 weeks of hypnotherapy. Following the course of hypnotherapy, rectal pain sensitivity was reduced in the subgroup that had been hypersensitive to stimuli in the rectum before treatment. Conversely, rectal sensitivity tended to increase in the subgroup that had low sensitivity before treatment (although this latter finding was not statistically significant). Reduction in gut pain sensitivity was associated with a reduction in clinical abdominal pain. These results suggest that hypnotherapy for IBS may work at least partly by normalizing uncomfortable bowel perception in those patients who have abnormally high gut sensitivity, while leaving normal sensation unchanged.

Gonsalkorale WM, Miller V, Afzal A, Whorwell PJ. Long term benefits of hypnotherapy for irritable bowel syndrome. Gut. 2003 Nov;52(11):1623-9. In this study, 204 IBS patients treated with a course of hypnotherapy completed questionnaires about symptoms, quality of life, anxiety, and depression before, immediately after, and up to six years following the treatment. Of all the treated patients, 71% showed improvement in response to treatment initially, and of those, 81% were still fully improved when re-contacted up to five years later. Quality of life and anxiety or depression scores were also still significantly improved at follow-up but showed some deterioration. Patients also reported fewer doctor visits rates and less medication use long-term after hypnosis treatment. These results indicate that for most patients the benefits from hypnotherapy last at least five years.

Gonsalkorale WM, Toner BB, Whorwell PJ. Cognitive change in patients undergoing hypnotherapy for irritable bowel syndrome. J Psychosom Res. 2004 Mar;56(3):271-8. Cognitive changes were evaluated in 78 IBS patients who completed a 12-session hypnosis treatment course, using the recently developed Cognitive Scale for Functional Bowel Disorders. Hypnotherapy resulted in improvement of symptoms, quality of life, anxiety and depression. Unhelpful IBS-related cognitions improved significantly after treatment, with reduction in the total cognitive score and all component themes related to bowel function. The amount of overall symptom reduction correlated with the degree of improvement on the cognitive scale.

Palsson OS, Turner MJ, Whitehead WE. Hypnosis home treatment for irritable bowel syndrome: a pilot study. Int J Clin Exp Hypn. 2006 Jan;54(1):85-99. A 3-month home-treatment version of the standardized North Carolina hypnosis protocol previously shown to improve all central IBS symptoms was completed by 19 IBS patients. Outcomes were compared to those of 57 matched IBS patients (1-to-3 matching) from a separate study receiving only standard medical care. Ten of the hypnosis subjects (53%) responded to treatment by 3-month follow-up (response defined as more than 50% reduction in overall IBS severity) vs. 15 (26%) of controls. Hypnosis subjects improved more in quality of life scores compared to controls. Having clinically significant anxiety scores was found to predict poor hypnosis treatment response. Hypnosis responders remained improved at 6-month follow-up. Response rate was lower in this study than previously observed in therapist-delivered treatment with the North Carolina protocol, but this was likely due to the fact that stricter criteria for significant improvement were used than in the other studies. The results of this study suggest that hypnosis home treatment with the North Carolina protocol may double the proportion of IBS patients who improve significantly in their bowel symptoms over a 6 month period.

Barabasz A, Barabasz M. Effects of tailored and manualized hypnotic inductions for complicated irritable bowel syndrome patients. Int J Clin Exp Hypn. 2006 Jan;54(1):100-12. This small clinical pilot study provided preliminary data on the effects of hypnotic inductions tailored to each IBS patient compared to a fully standardized (verbatim) protocol. A total of eight IBS patients previously unresponsive to any treatment were assigned randomly to either the tailored or standardized induction condition. Other than pre-testing for hypnotizability, the procedure followed for the standardized group (four subjects) was exactly as prescribed in the standardized North Carolina hypnosis protocol. The same scripts were used for the other (tailored) group of four patients except that the inductions were individualized. Patients in both subgroups showed favorable treatment response immediately post-treatment and at 10-month follow-up. Only the tailored group showed no incapacitating pain at post-treatment but greater emotional stress than the standardized group. The tailored group continued to improve and showed better results than the standardized group at 10-month follow-up, and the post-treatment emotional distress had decreased significantly.

Smith GD. Effect of nurse-led gut-directed hypnotherapy upon health-related quality of life in patients with irritable bowel syndrome. J Clin Nurs. 2006 Jun;15(6):678-84. This study conducted in Edinburgh, UK, measured the effects of a nurse-led gut-directed hypnotherapy on IBS. Seventy-five patients were treated with 5 to 7 1/2 hours of hypnotherapy, as well as receiving education and support. Diary results showed that the physical symptoms of abdominal pain and bloating improved significantly after treatment. Significant improvement was also found after treatment in anxiety scores and in six out of eight health-related quality of life scores.

Al Sughayir MA. Hypnotherapy for irritable bowel syndrome in Saudi Arabian patients. East Mediterr Health J. 2007 Mar-Apr;13(2):301-8. This study investigated the effects of hypnotherapy in 26 Saudi Arabian IBS patients. Each patient completed a course of 12 weekly hypnotherapy session. Abdominal pain, bloating and life interference from bowel symptoms all improved significantly in the patient sample after they completed treatment. Quality of life improved more in male than in female patients, and bowel habit dissatisfaction was reduced more in female than in male patients.

Vlieger AM, Menko-Frankenhuis C, Wolfkamp SC, Tromp E, Benninga MA. Hypnotherapy for children with functional abdominal pain or irritable bowel syndrome: a randomized controlled trial. Gastroenterology. 2007 Nov;133(5):1430-6. This Dutch study compared the effectiveness of six sessions of hypnotherapy over 12 weeks with results from standard medical treatment combined with six sessions of supportive therapy, in children with functional abdominal pain or IBS. Fifty-three children ranging in age from 8 to 18 years, with functional abdominal pain (31 patients) or IBS (22 patients), were randomly assigned to either hypnotherapy or the comparison treatment. Pain scores decreased significantly in both groups from baseline to 1 year follow-up, but the hypnotherapy group showed significantly greater reduction in pain. At one-year follow-up, treatment was judged successful for 85% of the hypnotherapy group and 25% of the comparison group (p <0.001).

Lindfors et al. Effects of gut-directed hypnotherapy on IBS in different clinical settings-results from two randomized, controlled trials. Am J Gastroenterol. 2012 Feb;107(2):276-85. This pair of controlled research trials in Sweden investigated the effects of 12 sessions of gut-directed hypnotherapy for IBS in two different clinical settings. In study 1, 90 patients were randomly assigned to receive either hypnotherapy or supportive therapy in psychology private practices, whereas in the second study 48 patients were randomly assigned to either gut-directed hypnotherapy or a waiting list in a small county hospital. Gastrointestinal symptom severity and quality of life were evaluated at baseline, at 3 months follow-up and after 1 year. In both the studies, IBS-related symptoms were improved at 3 months in the hypnosis groups but not in the control groups. In study 1, hypnosis produced a significantly greater improvement in IBS symptom severity than in the control group (P<0.05), and a trend in the same direction was seen in study 2. The benefits from hypnosis treatment seen at 3 months were sustained up to 1 year.

Lindfors et al. Long-term effects of hypnotherapy in patients with refractory irritable bowel syndrome. Scand J Gastroenterol. 2012 Apr;47(4):414-20. This article reported the findings of a retrospective Swedish survey of 208 IBS patients who completed a course of hypnosis hypnosis treatment. The Subjective Assessment Questionnaire was used to measure changes in IBS symptoms, and patients were classified as either treatment responders and non-responders based on their scores. Patients also reported changes in health-care use, use of medications for IBS symptoms, use of other non-pharmacological treatments, and whether they still actively used hypnosis. Immediately after hypnotherapy 49% of patients were responders, and 73% of these had improved further when they were surveyed at follow-up 2-7 years after hypnotherapy. The majority of the patients reported that they still used hypnotherapy on a regular basis at follow-up. Patients whose symptoms had shown good response to hypnosis used healthcare services less after treatment compared to non-responders.

Vlieger et al. Long-term follow-up of gut-directed hypnotherapy vs. standard care in children with functional abdominal pain or irritable bowel syndrome. Am J Gastroenterol. 2012 Apr;107(4):627-31. This was a follow-up study to a previously published trial (Vlieger et al. 2007 - see above) testing the use of hypnosis to treat IBS and functional abdominal pain in children. Here the investigators reportied the long-term effects of hypnotherapy versus standard medical treatment plus supportive therapy. All 52 patients treated in the previous study were invited to complete a standardized abdominal pain diary after an average period of 4.8 years had passed from the completion of treatment. After all that time, 68% of the patients who received hypnosis treatment versus only 20% of patients in the comparison group were in remission. Pain intensity scores were 2.8 in the hypnotherapy group at that timepoint, compared to 7.3 in the control group, and pain frequency scores averaged 2.3 for the hypnosis group and 7.1 for the control group. The amount of non-gastrointestinal body symptoms was also signficantly lower in the hypnosis group, but the two groups did not differ in quality-of-life scores, doctors' visits, or missed days of school or work in this follow-up assessment.

Gulewitsch et al. Brief hypnotherapeutic-behavioral intervention for functional abdominal pain and irritable bowel syndrome in childhood: a randomized controlled trial. Eur J Pediatr. 2013 Aug;172(8):1043-51. In this study, 38 children with IBS or functional abdominal pain, ranging in age from 6 to 12 years, were randomly assigned to either a standardized hypnotherapeutic-behavioral treatment (20 children) or to a waiting list condition (18 children). In the hypnosis treatment group, 11 of the 20 children 55.0%) showed clinical remission (defined as 80% or greater improvement), while only one child (5.6%) in the waiting list condition had such degree of improvement. Pain scores and pain-related disability improved significantly more in the hypnosis treatment group than in the the waiting list condition.

Moser et al. Am J Gastroenterol. Long-term success of gut-directed group hypnosis for patients with refractory irritable bowel syndrome: a randomized controlled trial. 2013 Apr;108(4):602-9. Ninety IBS patients who had failed to show response to usual treatment were randomly assigned to receive one of two types of group treatment: Either supportive talk therapy sessions or gut-directed hypnosis treatment in groups. Both interventions were a series of 10 weekly sessions over 3 months. Significantly more hypnosis patients than supportive group patients were improved after treatment (60.8% vs. 40.9%) and over 15 months the difference became even more significant (54.3% vs. 25.0% improved). The researchers also found that physical and psychological well-being in the hypnosis group participants improved significantly more compared to patients just getting standard medical care.

Gerson et al. Group hypnotherapy for irritable bowel syndrome with long-term follow-up. Int J Clin Exp Hypn. 2013;61(1):38-54. Seventy-five IBS patients were treated in groups with the standardized North Carolina IBS Hypnosis Protocol and their symptom status and quality of life tested at multiple time points up to 12 months after treatment. Compared to pre-treatment symptom severity there was a significant reduction in IBS symptoms after treatment as well as at 3, 6, and 12 months follow-up. Sixty percent of the treated patients showed clinically significant improvement in IBS.

Dobbin A, Dobbin J, Ross SC, Graham C, Ford MJ. Randomised controlled trial of brief intervention with biofeedback and hypnotherapy in patients with refractory irritable bowel syndrome. J R Coll Physicians Edinb. 2013;43(1):15-23. This study compared brief interventions with either three sessions of biofeedback or three sessions of hypnotherapy for women with treatment-refractory IBS symptoms. A total of 61 women completed the study. Both hypnosis and biofeedback treatment were found equally effective at improving IBS symptom severity scores, total non-gastrointestinal symptom scores and anxiety and depression ratings during 24 weeks follow-up. It should be noted that the hypnosis treatment used in this study - only three sessions for each patient - is the shortest treatment course (fewest sessions) used in any published study of hypnosis for IBS to date.

Lowén MB, Mayer EA, Sjöberg M, Tillisch K, Naliboff B, Labus J, Lundberg P, Ström M, Engström M, Walter SA. Effect of hypnotherapy and educational intervention on brain response to visceral stimulus in the irritable bowel syndrome. Aliment Pharmacol Ther. 2013 Jun;37(12):1184-97. The purpose of this study was to examine how the brains of IBS patients respond differently to sensations from their bowels after a course of either hypnotherapy or (for comparison) an educational intervention also designed to treat IBS. Signals indicating the amount of brain activity in different parts of the brain were measured by using functional Magnetic Resonance Imaging (fMRI) while a balloon was inflated in the bowel (rectum) of the subjects. A total of thirty-one female patients completed treatment and testing. IBS symptoms improved similarly and significantly in both treatment groups. Participants whose symptoms improved from either type of treatment showed lessened brain response to intense balloon distension afterwards, and their brains reacted more like normal individuals to the gut sensations produced by those balloon distensions. However, patients in the hypnosis group showed reduction in activity in somewhat different brain centers after treatment (posterior insula) compared to the education group, suggesting that hypnosis treatment may perhaps have some specific or unique therapeautic effects on brain activity in IBS patients.

Miller V, Carruthers HR, Morris J, Hasan SS, Archbold S, Whorwell PJ. Hypnotherapy for irritable bowel syndrome: an audit of one thousand adult patients. Aliment Pharmacol Ther. 2015 May;41(9):844-55. This article summarized outcome of hypnotherapy for one thousand IBS patients treated in a gastroenterology hypnotherapy unit in Manchester, England. All the patients were treated with 12 sessions of hypnotherapy following the structured treatment approach of the Manchester group. Overall, 76% of the patients improved from the treatment. Success rates were higher for females than males (80% vs. 62%) and slightly higher in patients with anxiety (79% vs 71%). In addition to bowel symptom improvement, non-gastrointestinal symptoms also improved significantly on average after treatment, and hypnotherapy also improved quality of life scores.

Lövdahl J, Ringström G, Agerforz P, Törnblom H, Simrén M. Nurse-Administered, Gut-Directed Hypnotherapy in IBS: Efficacy and Factors Predicting a Positive Response. Am J Clin Hypn. 2015 Jul;58(1):100-14. This study evaluated the effectiveness of standardized nurse-administered hypnotherapy protocol that was a Swedish-language extended variant of the North Carolina protocol, and aimed to identify factors that predicted good treatment outcome. Eighty-five patients received 12 weekly sessions of individual hypnotherapy by a nurse. The symptoms of 58% of the patients showed improved from the treatment, and of these 82% showed favorable clinical response already half-way through the treatment course (after 6 sessions). Women had a higher response rate than men to the treatment.

Rutten et al. Home-Based Hypnotherapy Self-exercises vs Individual Hypnotherapy With a Therapist for Treatment of Pediatric Irritable Bowel Syndrome, Functional Abdominal Pain, or Functional Abdominal Pain Syndrome: A Randomized Clinical Trial. JAMA Pediatr. 2017 May 1;171(5):470-477. In this study in the Netherlands, the investigators compared the benefits of two different types of hypnosis treatment for children with IBS. 250 children were randomly assigned to receive either a course of individual hypnotherapy with a therapist (128 children) or hypnotherapy using audio recordings at home (132 children). The treatment lasted 3 months for both groups, and consisted of 6 sessions for the group seeing a therapist, and home practice at least 5 days a week with the audio recordings for the audio hypnosis group. Immediately after treatment, success rates were 50.1% among the therapist-treated children and 36.8% among those using audio recordings. One year after treatment, successful improvement in IBS was seen in 71.0% of the therapist-treated children, and 62.1% in those using audio recordings. In spite of slightly numerically higher success rates with therapist-administered treatment, the audio treatment was not statistically inferior. The study indicates that much of the benefit of hypnosis treatment for IBS in children can be achieved in a more cost-effective manner by using audio recordings rather than face-to-face treatment by a therapist.

Flik CE, Laan W, Zuithoff NPA, van Rood YR, Smout AJPM, Weusten BLAM, Whorwell PJ, de Wit NJ. Efficacy of individual and group hypnotherapy in irritable bowel syndrome (IMAGINE): a multicentre randomised controlled trial. Lancet Gastroenterol Hepatol. 2019 Jan;4(1):20-31. This largest randomized controlled trial of hypnosis treatment to date for IBS compared treatment outcomes for 142 patients treated in individual hypnotherapy, 146 treated in group hypnotherapy, and 54 control patients who received education about IBS (control group). The patients were primary and secondary care patients at 11 different hospitals in the Netherlands. Treatment type was randomly assigned to participants, and each patient received 6 session of their assigned intervention. The primary outcome measure was the patients' self-reported adequate relief of IBS symptoms. In the intention-to-treat analysis, where patients who dropped out were included in the results, 40.8% in the individual hypnotherapy group, 33.2% in the group hypnotherapy, and 16.7% in the control group reported adequate IBS symptom relief at 3 months. At 12 months, 40.8% of individual hypnotherapy patients, 49.5% of group hypnotherapy group, and 22.6% of education control group patients reported adequate relief. Hypnotherapy was significantly more effective than the education control group at both those time points. When only treatment completers were included in data analysis, adequate IBS relief was attained by 49.9% in the individual hypnotherapy group vs. 42.7% in the group hypnotherapy group at 3 months, and those numbers were 55.5% vs. 51.7% at 12 months. Outcomes for group hypnotherapy were not statistically significantly inferior to individual hypnotherapy at either time point.

Peter J, Fournier C, Keip B, Rittershaus N, Stephanou-Rieser N,Durdevic M, Dejaco C, Michalski M, Moser G. Intestinal Microbiome in Irritable Bowel Syndrome before and after Gut-Directed Hypnotherapy. Int J Mol Sci. 2018 Nov 16;19(11). pii: E3619. doi: 10.3390/ijms19113619. This was the first-ever study to examine whether the composition of gut bacteria (intestinal microbiota) in the bowels of IBS patients changes after hypnotherapy. 38 IBS patients (by Rome-III diagnostic criteria) of all IBS subtypes were treated with 10 weekly group sessions of GHT, and stool samples were collected before and after treatment for microbiota analysis. The bowel symptoms of IBS were significantly reduced on average after hypnosis treatment, and psychological distress and well-being also improved significantly. Adequate relief of IBS symptoms was reported by 84% of the patients after the hypnosis treatment. However, no significant changes were found in intestinal gut microbiota composition. The findings of this novel study suggest, perhaps not surprisingly, that hypnosis improves IBS mostly via effects that are relatively independent of microbiota composition -- most likely, through alterations in the central nervous system's control of the gut.

Hasan SS, Pearson JS, Morris J, Whorwell PJ. SKYPE HYPNOTHERAPY FOR IRRITABLE BOWEL SYNDROME: Effectiveness and Comparison with Face-to-Face Treatment. Int J Clin Exp Hypn. 2019 Jan-Mar;67(1):69-80. This study compared hypnotherapy for IBS by Skype to in-person treatment in clinic. Using a 50-point on the validated IBS-SSS as the primary outcome measure, the investigators found that the IBS symptoms of 65% of patients improved significantly after Skype hypnotherapy and 76% after in-person treatment. On each of the other outcome measures, both Skype and in-person treatment showed significant positive therapeutic effects but the impact on each measure was numerically smaller in the Skype treatment than the face-to-face treatment: Overall IBS symptom severity (-94.1 vs. -129.2), non-gastrointestinal symptom score (-52.3 vs. -64.8), quality of life (+56.4 vs. +66.2), anxiety (-3.3 vs. -3.0), depression (-1.7 vs. -2.5), and pain reduction of 30% of more (44% vs. 62%). These results indicate that hypnotherapy via Skype (or similar Internet video-conferencing technologies) is effective but may not have quite as much therapeutic impact as face-to-face treatment. However, as the authors point out, the Skype option potentially enables many more patients to access this form of treatment.